This invention relates generally to flat panel display devices and particularly to a beam guide structure having continuously shielded longitudinal sides for use in such devices.
U.S. Pat. No. 4,101,802 discloses a flat panel display device including two beam guide meshes held in a spaced parallel relationship by metal spacers. The spacers extend the entire length along both sides of the beam guide meshes. The beam guide meshes include a plurality of apertures which are arranged in columns longitudinally along the meshes and in rows transversely across the meshes. The columns of apertures in the two meshes are transversely aligned so that the columns of apertures serve as beam guides for electron beams which propagate in the space between the two meshes.
This structure is operationally satisfactory for purposes intended. However, problems arise because the transverse alignment and relative longitudinal positioning of the apertures in the two guide meshes must be very accurately maintained in order for the electron beams to effectively propagate the full length of the channels. The apertures must be dimensioned and aligned to tolerances in the order of 1 mil. Additionally, the longitudinal alignment of the spacers along the sides of the meshes must be held to equally close tolerances. For those reasons, initial alignment of the many parts and the subsequent maintaining of such alignment during joining of these parts is a very difficult and costly task with the technology presently available.
U.S. patent application Ser. No. 125,822, filed Feb. 29, 1980 by Marvin Allan Leedom, now U.S. Pat. No. 4,330,735, entitled "Beam Guide Structure For Flat Panel Display Device" and assigned to RCA Corporation, the assignee of the instant application, also discloses a flat panel display device in which electron beams are propagated between spaced parallel beam guide meshes. In this device, the spaced parallel relationship of the beam guide meshes, and the focus and acceleration meshes which are spaced therefrom, are held in the desired positions and orientations by a plurality of insulative members in which the edges of the meshes ae embedded. This structure is also satisfactory for the purposes intended and eases the difficulty of holding the meshes in the desired positions and orientations during joining. However, problems nevertheless arise because the longitudinal sides of the electron beam propagation spaces between the beam guide meshes are open thereby permitting the insulative members to be charged by electrons and distort the electron beams.
The instant invention overcomes these difficulties by the provision of an electron beam guide structure which is simple to accurately fabricate and assemble and which provides continuously shielded longitudinal sides to isolate the propagating electron beams from the effects of influences outside of the guide meshes.